Fuel supply for opposed cylinder engines



May' 3, 1949. E. c. KIEKHAEFER FUEL SUPPLY FOR OPPOSED CYLINDER ENGINESFiled March 9, 1946 4 Sheets-s l May 3, 1949. E. c. KIEKHAEFER FUELSUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9. 1946 4 Sheets-Sheet 2r 2 W m a a mm 5 r 7% N F 4 f N Z May 3, 1949. E. c. KIEKHAEFER2,469,117

FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9, 194a 4Sheets-Sheet :s

IIIIIII [in 012102 3 Elmer 6. Z'Mfiae/r v 7 J/I orney May 3, 1949. E. c.KIEKHAEFER FUEL SUPPLY FOR OPPOSED CYLINDER ENGINES Filed March 9, 19464 Sheets-Sheet 4 for transmitting i a carburetor as of the cylindersiPatented May 3, 1949 FUEL s'urru FOR orrosnn onnmna enemas ar c.menu-rev, Cedarburg,-Wis.

' This invent-ion relates toengine fuel systems vaporized'jruel mixturesfrom in the case of two-cycle engine operation. I v I I Theinvention'has been applied to the construction of high-powerlight weighttwo-cycle I V Application March 9.194s,- Serial No. 653,399

' "'e'cmii i. 101423-56) ofli'lg. 3 midway between the center lines orthe cylinders;

Fig. 'l is a-similar section taken on line 86 of Fig. 3, on the centerline of the cylinder rarair-cooied engines having a weight-to-powerratio. of one pound per horsepower and having two cylinders firingsubstantially simultaneously with their cranks disposed closely adjacenton the crankshaft and in opposition to each other.

In such engines the fuel enters the crankcase from the carburetor,mixing chamber or'ieed line and is pre-compressed therein for force feedinto the cylinders.

One of'the objects of the. present invention is of the crankcase intoseparate precompression chambers for the two cylinders andtherebyretiming the amount of ofisetforthe cylinders.

Another object of the invention is to, provide a simplerlighter weightrotary valve constructionfor admitting the fuel to the crankcase.

I Another object is to provide a smaller cranke ,case with thevolumetric capacity proportioned to thecylindersto obtain'a greater precompression of the'fuel.

Another object is to provideaycrankcasei which in relation to thevalveinlet' and transfer ports effects a more nearlyjequal delivery'offue1 to the two cylinders.

' to reduce engine vibrations resulting from oirsetting of thecylinders, byavoiding theseparation of the housing. The

' body is open and cheek extending acrossthe thest from the intake; and

Fig. 8 is a, detail section showing the baflle in elevation and the farcylinder in section. The engine illustrated has a central two throwcrankshaft I mounted for rotation in a housin 2' by means of a needlebearing 3 at the driving end of the shaft and a second needle bearing 4at the opposite end of the shaft.

The housing 2 is constructed to provide a minimum volume necessary toenclose the cranks in their operation. For this purpose the housinghasone end reduced in diameter to receive the needle bearing 3. Theother end of the housing has studs 5- on the outside for bolting acrankcase cover 6 thereto to seal the housing closed.

The housing 2 carries the engine cylinders I and 8 which are boltedthereto on opposite sides cylinders I and 8 have their axissubstantially paralleland offset longitudinally of the crankshaft justsufilcient'to accommodate the two' corresponding crankthrows 9 and illof shaft I in close juxtaposition.

. Thethrowslfl and, I0 have a common inner axis of shaft I.

Each throw 9 and 10 has an outer cheek l2 with a counterweight "l3opposite the corresponding crank.

'Another' object is to; compensate for. any-differences in possiblerichness of the fuel delivered to the two cylinders. V Anotherobjectisto providefor moreeffective lubricationof the cranks 'andbearings.

An embodiment of the; invention is illustrated in th e accompanyingdrawings inwhich:

' Figure 1 is a perspective viewer the engine with parts removed andsectioned;

. Fig.2 is an exploded perspectivefview of the crankshaft and rotaryvalve constructions; Fig. 3 is a section'through thecrankshaft housingand assembled taken on a plane axially of the shaft and at right'anglesto the center lines 1 two cylinders I and-8.

} axial section through the housing *and assembled parts taken at rightangles to,

Fig.3;

a transverse section through the hous-- eac line H of Fig. 3 on thecenter line oi thecyIinderneareStthe'intake; g 618a similar section,taken-callus The throws S and Hi have crankpinsj it upon which aremounted the connecting rods l5 having their outer e'nds pivoted to thewrist pins' IS inside the correspondingpistons I! for cylinders I and 8.1 r

- The crankpins ,are disposed diametrically opposite each other on thecrankshaft to provide "for substantially-simultaneous operation'of theThe port 18 is preferably on'the side of the cover 6 nearest the nearcylinder 1. The admission'condu'it 19 from a, carburetor, not shown,

I is also preferably disposed on the same side of the cover 6 as theport l8, but in the outer-wall of the cover insteadof the inner wall,and preferably above the port. A passage 20 through cover Gconnectsconduit IS with port l8. The'shaft I carries a single circular valvedisc 2| ,which presses against the inner wall of the cover 6 and isadapted, to alternately cover and port i Forthis purpose the disc 3 withand uncover the port It during a part of each revolution of the discwith shaft I.

The disc 2| is pressed against the cover 6 by a spring washer 23disposed between the disc and the adjacent cheek l2. The disc 2! isdriven by means of a pin 24 extending fromthe adjacent cheek l2,preferably in line with crank pin It, and into a recessin a boss 25 onthe face of the disc.

The cylinders 1 and 8 have cylindrical liners 26 in which the pistons l1reciprocate. A lateral offset 21 in housing 2 and in the outer wall ofeach cylinder provides a passage 28 for fuel to a transfer port 29through the corresponding liner 26 and into the cylinder.

Each cylinder 1 and. 8 is provided with an exhaust port 30 through itswall opposite the transfer port 29.

The inlet ports 29 and exhaust ports 30 for each cylinder are adapted tobe covered and uncovered by the'corresponding piston l1 as the latterreciprocates in the cylinder.

One of the problems in the construction of an engine of this type inwhich the fuel is fed into a singlechamber crankcase, is that ofobtaining a satisfactory equal distribution of fuel to the cylinders.Where the fuel supply to one cylinder is more lean than to the other thelean cylinder is apt to overheat.

In carrying outthe present invention a more nearly equal distribution offuel is obtained to the two cylinders by providing a bafiie 3| in themouth of ofiset passage 28 of housing 2 for the far cylinder 8 to directmore fuel into the far cylinder, and by locating the transfer port 29for far cylinder 8 at a slightly greater radial distance from the centerline of shaft I than the transfer port 29 of the near cylinder 1 so thatthe intake port for cylinder 8 is opened first.

The baflie 3| has its tip extend downwardly adjacent the path of thecorresponding crank and connecting rod so that fuel condensation on thebaflie drips onto the crank for lubricating the latter. The path of thenear crank is downwardly on the side of port l8 and upwardly towardbaffle 3| so that it tends to throw fuel in the direction of the bafliefor entrance into cylinder 8.

The location of port l8 circumferentially in the cover 6 is preferablyon the lowerside of the near cylinder 1 so that the near crank tends tosweep the fuel toward cylinder 8 in the rotation of the shaft.

The differential radial distance of the transfer ports 29 may beobtained by machining the face of the. cylinder pad 32 on housing 2 forthe near cylinder 1 to a distance from the aXis of shaft I about two onehundredths of an inch less than the corresponding distance for thecylinder pad 33 for cylinder 8. By reason of this differential betweenthe cylinder pad locations, the cylinder 8 is located at a greaterdistance from the axis of shaft l than is cylinder 1, which fact effectsan uncovering or opening of the transfer port 29 for cylinder 8 soonerthan for cylinder 1.

It is preferable to employ both ways of inducing more fuel into the farcylinder 8, although it is possible to utilize either one of the waysalone in a given structure.

The invention provides for a minimum axial offset of the cranks andcylinders, thereby greatly reducing the torsional forces resulting fromsimultaneously firing of the cylinders, and making it possible tolighten the weight of the crankcase without danger of over stressing thesame.

The feeding of fuel into the crank case from the end, and its equaldistribution into the opposite cylinders is also importantin providingfol light weight construction of the engine.

An additional bearing 34, preferably a ball bearing, may be'disposedadjacent the outer cheek l2 of the crank throw for cylinder 8. Oil seals35 and 36 should be provided at opposite ends of the crankcase. Anadditional oil seal, not shown. may be provided on the cam shaft fortimer 31.

Various embodiments of the invention may be employed within the scope ofthe accompanying claims. I

I claim:

1. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase anddifferently spaced from said crankshaft in diametrically opposedrelation with their center lines of!- set longitudinally of thecrankshaft just sufilcient to accommodate the corresponding crankthrowsside-by-side on the shaft, a single fuel inlet port for said crankcasedisposed in one end thereof on the side of the near cylinder thereto,and a rotary fuel inlet valve operable by said crankshaft to govern saidfuel inlet port and supply fuel to said crankcase.

2'. In an engine of the class described, a' crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase anddifferently spaced from said crankshaft in diametrically opposedrelation with their center lines offset longitudinally of the crankshaftto accommodate the corresponding crank throws side-by-side on the shaft,a single fuel inlet port for said crankcase disposed in one end thereofon the side of the near cylinder thereto, a fuel inlet valve operable bysaid crankshaft, to govern said fuel inlet port and supply fuel to saidcrankcase and means cooperating with the location of said inlet port toequalize the distribution of fuel from said inlet valve through the caseto the cylinders.

3. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows side-byside on the shaft, a fuel inlet valve at one end of thecrankcase operable by said crankshaft, and a baffle in said crankcasedisposed in the path of fuel moving therethrough from said inlet valveto equalize the distribution of fuel to the cylinders.

4. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows'side-byside on the shaft, said cylinders having transfer portscommunicating between the corresponding cylinders and the crankcase andadapted to be opened and closed by the pistons in the cylinders durinoperation'of the engine, a fuel inlet valve atone end of the crankcaseoperable, by the crankshaft in synchronism with the .movement of saidpistons, and means to effect .uncovering of the transfer port for thecylinder which tends to be most lean in fuel prior tothe uncovering ofthe transfer port for the other cylinder.

5. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows side-by-side on the shaft, said cylinders having transfer portscommunicating between the corresponding cylinders and the crankcase andadapted to be opened and closed by the pistons in the cylinders duringoperation of the engine, and a fuel inlet valve at one end of thecrankcase, the transfer port for the cylinder which tends to be mostlean being disposed at a greater distance from the center line of thecrankshaft than the transfer port for the other cylinder to provide forearlier injection of fuel into the lean cylinder.

6. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows side-by-side on the shaft, said cylinders having transfer portscommunicating between the corresponding cylinders and the crankcase andadapted to be opened and closed by the pistons in the cylinders duringoperation of the engine, and a fuel inlet valve at one end of thecrankcase, the cylinder pad of said crankcase for the cylinder tendingto be most lean in fuel being disposed at a greater distance from theaxis of the shaft than the cylinder pad for the other cylinder.

'7. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows side-by-side on the shaft, a fuel inlet valve atone end of thecrankcase operable by said crankshaft, and a baflle in said crankcasedisposed in the path of fuel moving therethrough from said inlet valveto equalize the distribution of fuel to the cylinders, said baflle beingdisposed adjacent the path of movement of one of the cranks and abovethe same to increase lubrication of the crank by dripping of oil fromthe baffle onto the crank.

8. In an engine of the class described, a crankcase, a crankshaftoperable therein, a pair of cylinders carried by said crankcase indiametrically opposed relation with their center lines offsetlongitudinally of the crankshaft to accommodate the corresponding crankthrows side-byside on the shaft, said cylinders having transfer portscommunicating between the corresponding during operation of the engine,a fuel inlet valve at one end of the crankcase operable by saidcrankshaft, and a baflle in said crankcase disposed in the path of fuelmoving therethrough from said inlet valve to equalize the distributionof fuel to the cylinders, said baiiie being disposed near the entranceto the transfer port for the cylinder tending to be most lean in fueland extending toward the corresponding crank throw to'direct more fuelinto said cylinder. 9. In an engine of the class described, a crankcase,a crankshaft operable therein, a pair of cylinders carried by saidcrankcase in diametrically opposed relation with their center linesoffset longitudinally of the crankshaft to accommodate the correspondingcrank throws side-by-side on the shaft, said cylinders having transferports communicating between the corresponding cylinders and thecrankcase and adapted to be opened and closed by the pistons-in thecylinders during operation of the engine, a fuel inlet valve at one endof the crankcase operable by said crankshaft,

and a baffle in said crankcase disposed in the path of fuel movingtherethrough from said inlet valve to equalize the distribution of fuelto the cylinders, said baflle being disposed near the entrance to thetransfer port for the cylinder tending to be most lean in fuel andextendin toward the corresponding crank throw to direct more fuel intosaid cylinder and extending close to the path of the crank to provideadded lubrication for the crank by dripping of fuel from the baflie asthe crank passes the same.

ELMER C. KIEKHAEFER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

